PubMed · 6741775
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
L Greenberg. 1984. Program on heat stress computation.. https://pubmed.ncbi.nlm.nih.gov/6741775/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
A general design for a thermal test object (TTO) is proposed. A number of novel features make the design particularly suitable for use as a standardised device for assessing the heating capability of diagnostic ultrasound beams. To assess performance, soft-tissue TTOs have been made containing thin-film thermocouples sandwiched between discs of tissue-mimicking gel. Installed in an appropriate measurement system, these TTOs exhibit excellent thermal and spatial resolution, allowing the ultrasound beam to be located rapidly and reproducibly. The measured temperature rise after 3 minutes of heating has been compared with theoretical predictions based on measured pressure distributions, and agreement is within 10%. Other studies have shown that soft-tissue- and bone-mimicking TTOs can be used to evaluate a wide range of ultrasound fields and that different physical tissue models can be simulated. It is concluded that this design would be suitable for providing reference assessments of the thermal hazard posed by diagnostic ultrasound under standardised conditions.
Folding pathways of large RNAs are poorly understood. We have addressed this question by hybridizing in vitro transcripts, which varied in size, to an array of antisense oligonucleotides. All transcripts included a common sequence and all but one shared the same start-point; the other had a small deletion of the 5' end. Minimal free energy calculations predicted quite different folds for these transcripts. However, hybridization to the array showed predominant features that were shared by transcripts of all lengths, though some oligonucleotides that hybridized strongly to the short transcripts gave weak interaction with longer transcripts. A full-length RNA fragment that had been denatured by heating and allowed to cool slowly gave the same hybridization result as a shorter transcript. Taken together, these results support theories that RNA folding creates local stable states that are trapped early in the transcription or folding process. As the transcript elongates, interactions are added between regions that are transcribed early and those transcribed late. The method here described helps in identifying regions in the transcripts that take part in long-range interactions.
The effect of sodium lactate (NaL) (0, 2.4 or 4.8%), in heating and recovery media, on Yersinia enterocolitica and Listeria monocytogenes numbers recovered from minced beef heated at 55 degrees C, was examined. Survivors were enumerated on selective media at pH 5.7/7.4 (Y. enterocolitica) or pH 5.7/7.2 (L. monocytogenes). Recovery of the organisms depended on the pH and NaL levels in the recovery medium. The heat resistance of Y. enterocolitica (P < 0.001) and L. monocytogenes (P < 0.01) decreased as the concentration of NaL in the minced beef increased from 0 to 2.4% or 4.8%. The thermal destruction of pathogens in foods processed using mild temperatures may be enhanced by the addition of 2.4% NaL.